Review of X-ray powder diffraction data of rhombohedral bismuth tri-iodide

1996 ◽  
Vol 11 (2) ◽  
pp. 91-96 ◽  
Author(s):  
L. Keller ◽  
D. Nason
Keyword(s):  
Rietveld Refinement ◽  
Room Temperature ◽  
Internal Standard ◽  
Standard Technique ◽  
Rietveld Analysis ◽  
Lattice Parameter ◽  
Parameter Determination ◽  
Data Set ◽  
X Ray ◽  
Diffraction Patterns

Single crystals of rhombohedral bismuth tri-iodide grown by physical vapor transport are possible candidates for room-temperature detectors. Previously reported, low angle reflections in X-ray diffraction patterns of various BiI3 starting powders are attributed to the BiI3 structure from Rietveld analysis. Accordingly, the lattice parameters of stoichiometric BiI3 are determined as a0=7.5192±0.0003 Å and c0=20.721±0.004 Å at room temperature. It also appears that lattice parameter determination using Rietveld refinement can lead to significant errors if experimental aberrations are present and their nature and magnitude are unknown. A modified internal standard technique is applied to the data set prior to Rietveld refinement for more reliable lattice parameter determination.

High-precision absolute lattice parameter determination of SrTiO3, DyScO3 and NdGaO3 single crystals

2012 ◽  
Vol 68 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Martin Schmidbauer ◽  
Albert Kwasniewski ◽  
Jutta Schwarzkopf
Keyword(s):  
High Resolution ◽  
High Precision ◽  
Room Temperature ◽  
Systematic Errors ◽  
Lattice Parameter ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Method

The lattice parameters of three perovskite-related oxides have been measured with high precision at room temperature. An accuracy of the order of 10−5 has been achieved by applying a sophisticated high-resolution X-ray diffraction technique which is based on the modified Bond method. The results on cubic SrTiO3 [a = 3.905268 (98) Å], orthorhombic DyScO3 [a = 5.442417 (54), b = 5.719357 (52) and c = 7.904326 (98) Å], and orthorhombic NdGaO3 [a = 5.428410 (54), b = 5.498407 (55) and c = 7.708878 (95) Å] are discussed in view of possible systematic errors as well as non-stoichiometry in the crystals.

Intermetallic Hydrides Based on (Zr-Ti)(Fe-Cr)2 Type of Compounds

2006 ◽  
Vol 514-516 ◽  
pp. 666-671 ◽  
Author(s):  
Sofoklis S. Makridis ◽  
C. Christodoulou ◽  
Mary Konstantakou ◽  
Th.A. Steriotis ◽  
M. Daniil ◽  
...  
Keyword(s):  
Hydrogen Pressure ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Paramagnetic Behaviour ◽  
Diffraction Patterns ◽  
Microstructural Studies ◽  
Dominant Phase

In this work, the (Zr-Ti)(Fe-Cr)2 based compounds have been synthesized while charging-discharging hydrogen ability has been examined. Relatively low hydrogen pressure has been used for the hydrogenation of the samples. After following the discharging procedure, a high desorbed amount of hydrogen ~180 (ml of H2)/(gr of the alloy) has been measured on the first 15 min by using a volumetric device. The crystal structure has been analyzed by means of x-ray diffraction (XRD) while a Rietveld analysis has been performed on the x-ray diffraction patterns and the characteristic MgZn2 type of structure has found to be the dominant phase in both compounds. The scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) have been used for microstructural studies and quantitative analysis, respectively. Magnetic measurements have been performed on the samples and a paramagnetic behaviour has found to be at room temperature.

Rietveld refinement of the crystal structure of γ-Mo4O11

1999 ◽  
Vol 14 (4) ◽  
pp. 284-288 ◽  
Author(s):  
Hoong-Kun Fun ◽  
Ping Yang ◽  
Minoru Sasaki ◽  
Masasi Inoue ◽  
Hideoki Kadomatsu
Keyword(s):  
Crystal Structure ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Rietveld Analysis ◽  
Powder Diffraction Data ◽  
Orthorhombic System ◽  
Space Group ◽  
X Ray

The crystal structure of γ-Mo4O11 was obtained at room temperature (296 K) by Rietveld analysis with X-ray powder diffraction data. The crystal belongs to orthorhombic system, space group: Pna21, Z=4, Mr=559.753 (Atomic weights 1977), Dx=4.1228 g/cm3, F(000)=1024.0, μ=451.293 cm−1 (Int. Tab. Vol. C, Table 4.2.4.2, p. 193, λ=1.540 60 Å), a=24.4756(5) Å, b=6.7516(1) Å, c=5.4572(1) Å, and V=901.80(3) Å3. The structure was refined to Rwp=5.60%, Rp=4.27%, Rb=3.36%, and Rf=2.74% for 65 parameters with 3541 step intensities and 3055 peaks. Goodness of the fit S=3.35.

scholarly journals Structure properties and dielectric relaxation of Ca0.1Na0.9Ti0.1Nb0.9O3 ceramic

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25358-25367 ◽  
Author(s):  
Hanen Ghoudi ◽  
Souad Chkoundali ◽  
Zeineb Raddaoui ◽  
Abdelhedi Aydi
Keyword(s):  
Solid State ◽  
Dielectric Relaxation ◽  
Rietveld Refinement ◽  
Solid State Reaction ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Diffraction Patterns ◽  
Structure Properties

In this paper, the synthesis of Ca0.1Na0.9Ti0.1Nb0.9O3 (CNTN) ceramic by a solid-state reaction is reported. The results of Rietveld refinement of X-ray diffraction patterns at room temperature showed a pure tetragonal perovskite (P4mm space group).

scholarly journals Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

Cerâmica ◽  
2014 ◽  
Vol 60 (356) ◽  
pp. 524-531 ◽  
Author(s):  
M. S. Conconi ◽  
M. R. Gauna ◽  
M. F. Serra ◽  
G. Suarez ◽  
E. F. Aglietti ◽  
...  
Keyword(s):  
Glassy Phase ◽  
Internal Standard ◽  
Rietveld Analysis ◽  
Internal Standard Method ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
X Ray ◽  
Porosity Evolution ◽  
Diffraction Patterns ◽  
Low Crystalline

The firing transformations of traditional (clay based) ceramics are of technological and archeological interest, and are usually reported qualitatively or semiquantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite), the low crystalline (metakaolinite and/or spinel type pre-mullite) and glassy phases evolution of a triaxial (clay-quartz-feldspar) ceramic fired in a wide temperature range between 900 and 1300 ºC. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 ºC) spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy) phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and materials properties. These correlations can be employed for materials characterization, design and processing control.

An indexing algorithm independent of peak position extraction for X-ray powder diffraction patterns

2017 ◽  
Vol 50 (5) ◽  
pp. 1323-1330 ◽  
Author(s):  
Alan A. Coelho
Keyword(s):  
Monte Carlo ◽  
Parameter Space ◽  
Powder Diffraction ◽  
Merit Function ◽  
Limited Range ◽  
Lattice Parameter ◽  
Peak Position ◽  
Parameter Determination ◽  
X Ray ◽  
Diffraction Patterns

Lattice parameter determination from X-ray powder diffraction patterns, called indexing, invariably requires the extraction of peak positions which are then used by indexing algorithms that are peak position dependent. The success of these algorithms depends on the accuracy of the extracted peak positions. Peak positions that do not overlap significantly with nearby peaks can be readily determined with great accuracy. However, in heavily overlapped regions it is difficult to determine the number of peaks and even more difficult to determine the peak positions accurately. This paper describes a new indexing algorithm,Lp-Search, that is implemented in the computer programTOPAS Version 7(Bruker AXS, Karlsruhe, Germany).Lp-Searchdoes not require peak position extraction nor does it require knowledge of the number of peaks present.Lp-Searchcombines Monte Carlo searches of lattice parameter space with a Pawley refinement used at the end of each search. Critical to the success of the Monte Carlo search is a new figure of merit function which allows the parameter space to be searched efficiently.Lp-Searchhas proved to be effective for patterns with heavily overlapped peaks; monoclinic to cubic lattices are successfully indexed in a matter of seconds and triclinic lattices within a minute or two. Diffraction patterns spanning a limited range, such that 30–40 peaks of the highestdspacing peaks are omitted, can be successfully indexed; this demonstrates the robust nature ofLp-Search.

Physical and Mechanical Properties of Cement Paste Were Used Partially with Fly Ash and Kaolin Waste

2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Partial Replacement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lime Water ◽  
Diffraction Patterns ◽  
Iron Mold

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.

Problems Associated with Kα Doublet in Residual Stress Measurements

1979 ◽  
Vol 23 ◽  
pp. 333-339
Author(s):  
S. K. Gupta ◽  
B. D. Cullity
Keyword(s):  
Residual Stress ◽  
Silicon Powder ◽  
Lattice Parameter ◽  
Diffraction Peak ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
The Difference ◽  
Similar Accuracy

Since the measurement of residual stress by X-ray diffraction techniques is dependent on the difference in angle of a diffraction peak maximum when the sample is examined consecutively with its surface at two different angles to the diffracting planes, it is important that these diffraction angles be obtained precisely, preferably with an accuracy of ± 0.01 deg. 2θ. Similar accuracy is desired in precise lattice parameter determination. In such measurements, it is imperative that the diffractometer be well-aligned. It is in the context of diffractometer alignment with the aid of a silicon powder standard free of residual stress that the diffraction peak analysis techniques described here have been developed, preparatory to residual stress determinations.

scholarly journals MOVPE Growth of Quaternary (Al,Ga,In)N for UV Optoelectronics

2000 ◽  
Vol 5 (S1) ◽  
pp. 412-424
Author(s):  
Jung Han ◽  
Jeffrey J. Figiel ◽  
Gary A. Petersen ◽  
Samuel M. Myers ◽  
Mary H. Crawford ◽  
...  
Keyword(s):  
Room Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Optoelectronic Devices ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Energy ◽  
Movpe Growth ◽  
Pl Emission

We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant- PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

X-Ray Diffraction Study of Hep Metals. I. Line Broadening in Polycrystalline Cd Powder

1974 ◽  
Vol 29 (12) ◽  
pp. 1771-1777 ◽  
Author(s):  
N. C. Haider ◽  
S. H. Hunter
Keyword(s):  
Room Temperature ◽  
Small Deformation ◽  
Correction Factors ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Fault Probability ◽  
Large Particle Size ◽  
X Ray ◽  
Melting Temperatures ◽  
Diffraction Patterns

Powder Cd of 99.999% purity was prepared at room temperature (25 °C) and x-ray diffraction patterns were obtained using CuKaα radiation with Ni-filter. The line broadening was analyzed after incorporating the appropriate correction factors. At room temperature Cd was found to have large particle size (653 A), small root mean square strain (.001), small deformation fault probability a (.003). and negligible growth fault probability β(0). Compared to other hep metals which have been studied earlier and which have higher melting temperatures, metal Cd is much less affected by mechanical deformation at room temperature.

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